Papermaking fabrics with contaminant resistant nanoparticle coating and method of in situ application

ABSTRACT

A papermaking fabric is treated by applying a nanoparticle type coating to improve their resistance to contamination by foreign matter in the papermaking system. The coating is applied during fabric manufacture and cured during heat setting. Alternatively, the coating applied or renewed by utilizing an existing shower or locating a spray boom or other suitable coating application device in the dryer section to apply the coating to the fabric in a controlled, uniform manner. Prior to application of the coating, the fabric is first thoroughly cleaned such as by showering or spraying, and then dried. Following controlled application of the coating, any excess material is removed by a suitable means, such as by vacuum, and the remaining coating on the fabric is then cured, either by utilizing the ambient heat of the dryer section or by a portable bank of heaters. In this manner, the fabric does not have to be removed from the machine in order to apply or renew the contaminant resistant coating.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.11/371,970, filed Mar. 9, 2006, which claims the benefit of U.S.Provisional Application No. 60/659,799, filed Mar. 9, 2005, all of whichare incorporated by reference as if fully set forth.

BACKGROUND

The present invention relates to methods for the in situ application ofcontaminant resistant coatings to papermaking fabrics, and papermakingfabrics so coated. In particular, the invention is directed to methodsfor the in situ application of nanoparticle coatings to papermakingfabrics that reduce machine down time.

Papermaking fabrics are used in connection with papermaking machines toboth form an embryonic web of paper from a pulp slurry and to carry itthrough various dewatering and drying processes to form various types ofpaper products. The papermaking fabrics are generally in the form of afine mesh, which can be of various configurations depending on theposition in the papermaking machine, and may include additional layersof batt, for example in certain press and dryer fabrics.

Particles suspended in the primarily cellulose fiber stock used to formthe paper may include pitches, adhesives, other glue-like substances aswell as other materials that have a propensity to stick to thepapermaking fabrics, reducing the fabric permeability and adverselyeffecting the performance of the papermaking fabric. Prior knownsolutions to address this problem have proposed coating the fabric withan anti-contaminant material in order to enhance the anti-stickingproperty of the fabric and maintain the fabric cleaner for a longerperiod of time after it is installed on a papermaking machine. However,the prior known coatings wear off through use, resulting in diminishedperformance of the papermaking fabric. Additionally, the thickness ofthe coating itself had to be very small so that the coating itself didnot reduce the fabric permeability.

While initial coatings had a fairly short life, one prior knownanti-contaminant coating was developed containingpolytetrafluoroethylene (PTFE) that was applied to the fabric using abath and then cured at a temperature of 200° F. to 400° F. prior toinstalling the fabric on the papermaking equipment. Thisanti-contaminant coating had a longer life, but was still subject towear.

Nanoparticle coatings are also known, such as described in e.g.: WO02/50191 Solvent-Poor Sol-Gel Systems; U.S. Pat. No. 6,482,525 Methodfor producing themoshaped substrates coated with a SOL-Gel Lacquer; U.S.Pat. No. 6,620,514 Nanostructured forms and layers and method forproducing them; U.S. Pat. No. 6,607,994 Nanoparticle-Based permanenttreatments for textiles; U.S. Pat. No. 6,649,266 Substrates producedwith a microstructured surface; U.S. Pat. No. 6,629,070 Nanostructuredmoulded bodies; WO 03/014232A1 Material for producing abrasion proofhydrophobic and/or oleophobic coatings. The generally accepteddefinition of “nanoparticles” is particles with a size less than about100 nm. Such coatings have been used in connection with various types offabric, for example for contamination resistance or to increase wearlife. However, they have not been specifically used in connection withpapermaking fabrics

In use, it is also known to remove papermaking fabrics having asubstantial remaining useful life from a papermaking machine forre-coating and subsequent re-installation in order to maintain thebenefit of anti-contaminant coatings. However, this entails substantialadditional cost and down time for the papermaking machine.

Thus, it would be desirable if a contamination resistant nanoparticlecoated papermaking fabric were available which provided anti-stickingproperties when installed in the environment for which it is intended.It would be further desirable if methods existed to allow such fabrics,as well as those not so treated, to be coated or recoated with a eitheror both a hydrophobic or oleophobic contamination resistant nanoparticlecoating while installed in the environment for which they are intended(i.e.: in situ application of the coating). It would also be desirableif methods existed which would allow for in situ application of thecontamination resistant hydrophobic and/or oleophobic nanoparticlecoating to selected areas only of these fabrics.

SUMMARY

A contaminant resistant industrial textile, such as a papermakingforming, dryer or Through-Air Drying (TAD) fabric, and a method ofrendering such a fabric contamination resistant is provided. In a firstembodiment of the invention, which is presently preferred, a water basednanoparticle type contaminant resistant coating is applied to anindustrial textile such as a papermaking fabric, while the fabric isinstalled in place on the papermaking machine (i.e. it is ready to runor is in operation but not making paper). The coating may have either,or both, hydrophobic or oleophobic characteristics, and is heat cured onthe papermaking fabric using existing heat sources which are alreadypresent in the papermaking equipment, or through the use of auxiliaryheaters located adjacent to the fabric. Preferably, when the fabric isheat cured on the papermaking equipment, this is done at temperatures ofbetween about 32° C. (90° F.) to about 120° C. (248° F.) by means of theexisting heat source or the auxiliary heaters. All temperatures are asmeasured either immediately adjacent to, or at, the surface of thetextile.

Alternatively, only selected portions of an industrial textile such as apapermaking fabric are treated with the water based nanoparticle typehydrophobic or oleophobic contaminant resistant coating while the fabricis installed in place on the papermaking machine (i.e. it is ready torun or is in operation, but not making paper). The coating is applied,for example, to the lateral side edges of the fabric only and thoseareas alone are subsequently heat cured in situ using existing heatsources already present in the papermaking equipment, or auxiliaryheaters located adjacent to the fabric. Preferably, when the coating iscured in situ on the industrial textile, this is done at temperatures inthe range of from about 32° C. (90° F.) to about 120° C. (248° F.).

In a second embodiment of the invention, the coating is applied to thetextile after it has been manufactured, but prior to delivery to thecustomer for which it is intended. The coating is heat cured on thetextile manufacturing equipment so as to bond it securely to the fabric,using temperatures which are in the range of from about 52° C. (125°F.), to about 204° C. (400° F.), all such temperatures being measuredeither immediately adjacent to, or at, the surface of the textile.

Preferably, the coating is heat cured prior to installation of thetextile in the environment for which it is intended at temperatures offrom about 66° C. (150° F.) to about 177° C. (350° F.); more preferably,the coating is heat cured prior to installation at a temperature of fromabout 66° C. (150° F.) to about 149° C. (300° F.).

Preferably, the entire surface area of the fabric is coated with thewater based nanoparticle type contaminant resistant coating and issubsequently heat treated at temperatures of from about 52° C. (125°F.), to about 204° C. (400° F.), such temperatures being measuredimmediately adjacent to, or on, the textile surface. Alternatively, onlyselected portions of the textile surface are so treated and heat cured.

It is well known that many textile materials, including the PET(polyethylene terephthalate) yarn commonly used in the manufacture ofpapermaking fabrics, begin to lose their dimensional stability atelevated temperatures above about 93° C. (200° F.). If the entire fabricis to be exposed to temperatures greater than about 93° C. (200° F.)such as in a heatsetting process at the manufacturer's facilities, it isrecommended that some means of dimensional stability control be appliedso as to maintain certain dimensional and other physical properties ofthe fabric within desired ranges. One means of doing this is to restrainthe fabric (i.e. apply lateral and/or longitudinal tension) by means ofa tenter; however, other suitable means may be used without departingfrom the scope of the present invention.

In either or both of the first or second embodiment of the invention,the nanoparticle surface treatment preferably includes both ahydrophobic and oleophobic characteristic. However, effective resultshave been obtained by coating the fabric with a coating having only oneof a hydrophobic or oleophobic characteristic. It is also possible toperform multiple coating and curing steps to form a composite coating onthe fabric, for example, with a first coating layer having one of ahydrophobic or oleophobic characteristic, and a second or subsequentcoating having the other of the hydrophobic or oleophobiccharacteristic, or another desired characteristic. This providesenhanced contamination resistance for the papermaking fabrics accordingto the invention.

In another aspect, the invention is also directed to papermaking fabricshaving improved contamination resistance produced by the processesaccording to the invention. Such fabrics have a greatly improvedRelative Contamination Resistance value in comparison to fabrics thathave not been treated in accordance with the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be explained in more detail in connectionwith the drawings in which presently preferred embodiments are shown.

FIG. 1 is a side view, in schematic form, of a dryer section of apapermaking machine with a water based nanoparticle type hydrophobic oroleophobic contaminant resistant coating being applied to the fabric andcured on the machine in accordance with the present invention.

FIG. 2 is a perspective view of a spray boom that can be placed adjacentto the dryer fabric while it is on a papermaking machine in order toapply a nanoparticle type contaminant resistant coating in accordancewith the present invention.

FIG. 3A is a perspective view of a spray boom having a size less thanthe width of the dryer fabric shown in a first position to coat a firstportion of the fabric.

FIG. 3B is a perspective view of a spray boom having a size less thanthe width of the dryer fabric shown in a second position to coat aremaining portion of the fabric. This process could be used to treatjust the edges of a fabric that was subject to contamination orhydrolysis on the edges and prevent premature removal of the fabric forproblems outside of the sheet area.

FIG. 4 is a perspective view of a portable heater shown in position forcuring the coating applied to the fabric.

FIG. 5 is a block diagram illustrating a second embodiment of theprocess according to the invention for improving the contaminationresistance properties of an industrial fabric used for papermaking bycoating the fabric prior to heat setting and curing the coating duringheat setting of the fabric.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Certain terminology is used in the following description for convenienceonly and is not considered limiting. Words such as “front”, “back”,“top” and “bottom” designate directions in the drawings to whichreference is made. This terminology includes the words specificallynoted above, derivatives thereof and words of similar import.Additionally, the terms “a” and “one” are defined as including one ormore of the referenced item unless specifically noted.

The term “tenter” as used herein refers to a device that stretches atextile to its finished width and straightens the weave by the action oftwo diverging endless chains each equipped with a series of pins, clipsor clamps that hold the edges of the cloth and convey it over hot rollsor through a hot air box. It will be obvious to those of skill in theart that other suitable means may be employed so as to achieve thedesired end result without departing from the spirit of the presentinvention.

All temperatures referenced herein in connection with heatsetting andcuring the coated industrial textiles of this invention are measured at,or immediately adjacent to a surface of a textile by suitable means.

According to a first embodiment of the invention, the industrialtextile, such as a through air-dryer (“TAD”) fabric, forming fabric ordryer fabric 10, is first cleaned in place (i.e. in the forming or dryersection of a papermaking machine in its normal location), with thepapermaking machine 12 moving the fabric 10 on a slow or “crawl” speedby showering, either with water or, optionally, water including asurfactant and/or pH adjustment as required. This helps to ensure thatas much of any contaminants as have become attached to the fabric 10during use are removed so that satisfactory bonding of the nanoparticlematerials to the yarns of the fabric 10 in the subsequent fabrictreatment occurs. The shower 14 is preferably an existing papermachineshower, but a portable spray boom 16, such as that shown in FIG. 2, orother suitable external cleaning system may be employed. A vacuum box 22or other air treatment may be located on either or both of the paperside (PS) and machine side (MS) of the fabric following this cleaningshower so as to remove any excess water and/or cleaning fluids from thefabric and to dry it.

After the fabric 10 is cleaned and dried, a suitable hydrophobic and/oroleophobic nanoparticle type contaminant resistant liquidsolution/suspension 20 can be applied to at least one fabric surface,preferably by coating roll application, spraying or showering it inliquid form onto the at least one surface. Preferably, this contaminantresistant liquid solution/suspension is a water-based three-componentsystem consisting of:

1. an adhesion promoter,

2. nanoparticulate material comprised of an organic prepolymer, and

3. a fluorocarbon polymer.

Preferably, the adhesion promoter is an organofunctional adhesionpromoter having a functional group which is one of a vinyl-,methacrylate-, epoxy-, amino-, or mercapto-group.

Preferably, the nanoparticulate material is comprised of organicnanoparticles such as nanowaxes including polyethylene or polypropylene,or prepolymers of condensated silanes such as methyltriethoxysilane,propyltriethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, orphenyltrimethoxysilane and the like. An advantage provided by the use ofthe silane prepolymers is the possibility to react with the adhesionpromoter to build a network of organic prepolymer.

Preferably, the fluorocarbon polymer is a fluoroacrylate orfluoroalkyl-polyurethane copolymer. Other similar fluorocarbon polymersmay be suitable.

These three materials are combined in a ratio of from about 10-25% byweight adhesion promoter, 10-25% by weight nanoparticulate material, andfrom about 30-70% by weight fluorocarbon polymer to provide the desiredthree component system.

The coating can be applied by means of an existing shower 14 such as mayalready be located in the papermaking machine, as shown in FIG. 1.Alternatively, the coating 20 may be applied by appropriately locating aremovable spray boom 16 or other suitable means through which thecoating is applied to the fabric. The spray boom 16 preferably includesa plurality of spray nozzles 18, and is supported on legs 19 or may beclamped or is otherwise positionable adjacent to the fabric in apapermaking machine 12. The fabric 10 is coated in place (e.g. onlocation in the TAD dryer section) by using the selected coating deviceand without removing the fabric 10 from the machine Any excess coatingmaterial 20 is removed by a vacuum slot box 22 downstream of theapplication device and is recycled into the coating system.

Spray conditions and treatment times are calculated to yield efficientcoverage of the papermachine fabric 10 and to ensure successful bondingof the nanoparticles to the yarns of the fabric 10. The speed of thefabric 10 and temperature of treatment are calculated to give the bestpossible coating integrity. Typical coating temperatures for a fabricunrestrained by a tenter in the cross machine direction are from about32° C. (90° F.) to about 120° C. (248° F.). Typical applications arecalculated to use about 23 g of active material per square meter offabric surface. The material can be applied in a range of 0.5 to 30%active nano-solids in water dilution. Preferred active solidsconcentrations in use have been 2.5 to 10% solids. The excess amount ispreferably removed with a vacuum slot downstream of the area whereapplication occurs.

Fabrics which are very thick may require higher coating rates per unitarea to completely cover the interior volume of the fabric. Fabricspeeds of 2.5 to 4 meters per minute (8-12 feet per minute) are typical,but must be adjusted for the residence time in the heater zone to avoidover heating above the dimensional stability point of the yarn material(except in the case of final heatset in fabric manufacture where atenter controls the dimensions of the fabric. The coating 20 is thencured, preferably by passing across the heated dryer rolls 24 of thedryer section of the papermaking machine 12, so as to ensure a good bondwith the component yarns of the fabric 10.

The coating 20 can be optionally heat cured using a portable infraredheater bank 26 or the like, but it is preferably cured by means of heatderived from the dryer system of the machine, especially in a TAD, orthrough-air dryer section. It is believed that the TAD section of atissue machine would be especially well suited to the application andcuring of this coating 20 as there is sufficient heat of at least 49° C.(120° F.) to cause the coating 20 to cure and thus securely attachitself to the yarns. Also, many of the elements required for successfulapplication (i.e. shower, vacuum slots and rolls, heat) are alreadypresent in the dryer section or can be readily adapted to this type ofmachine. In any event, the temperature of the environment in which thefabric is located must be sufficient so that the coating is cured insitu. Preferably, the temperature of the papermaking environment inwhich the fabric is located is in the range of from about 32° C. (90°F.) to about 120° C. (248° F.). More preferably, the temperature is inthe range of from about 49° C. (120° F.) to about 93° C. (200° F.). Mostpreferably, the temperature is in the range of from about 60° C. (140°F.) to about 82° C. (180° F.).

It is possible to cure the coating by any of a variety of heat treatmentmeans, such as by use of a temporary bank of infrared heaters 26, asshown in FIG. 4. This coating equipment system can be designed as aportable unit that is self contained and could be either purchased andused within a paper mill or rented for the regeneration process.Additionally, as shown in FIGS. 3A and 3B, the equipment does not haveto be full width of the machine 12 and could be moved across the widthof the fabric 10 between passes to facilitate the coating process. Forexample, a first half of the fabric 10 can be coated with the spray boom16 in a first position. The second half of the fabric 10 can then becoated with the spray boom 16 in a second position, as shown in FIG. 3B.Three or more passes could be utilized depending on the size of thespray boom 16 and the width of the fabric 10. Experience has shown thatrepeat applications (i.e. one application or layer spread over anexisting one) do not adhere to one another so overlapping applicationswould not be a problem as they would be vacuumed off or otherwiseremoved by the downstream vacuum. This property of the coatingeliminates the phenomenon of “windowpaning” whereby a thin film ofcoating would form and remain over a mesh opening, effectively blockingthe mesh at one or more locations.

Alternatively, the apparatus could be designed or used to just coat theedges of the fabric to prevent the typical causes of premature fabricfailure in this area, such as contamination by “stickies” and similarforeign matter in the paper web, and hydrolytic degradation of thecomponent yarns at the fabric edges. We have found that, surprisingly,lateral edges of TAD fabrics which have been coated with the hydrophobicor oleophobic nanoparticle type contaminant resistant liquidsolution/suspension and subsequently cured have remained relativelysupple and do not exhibit typical signs of hydrolytic degradation whencompared to similar but untreated fabrics.

The coating 20 with the nanoparticle surface treatment preferablyincludes both a hydrophobic and oleophobic characteristic. It is alsopossible to perform multiple coating and curing steps to form acomposite coating on the fabric 10, for example, with a first coatinglayer having one of a hydrophobic or oleophobic characteristic, and asecond or subsequent coating having the other of the hydrophobic oroleophobic characteristic, or another desired characteristic. Thisprovides enhanced contamination resistance for the papermaking fabricsaccording to the invention.

Once the fabric has been successfully coated and the coating cured sothat it is reasonably well bonded to the fabric surface and yarns, thecoating equipment is removed from the machine and paper productionresumed.

According to a second embodiment of the invention, the fabric is treatedduring manufacture so as to render it contamination resistant byapplying a hydrophobic and/or oleophobic water based nanoparticle typecontaminant resistant coating, and then curing it so that theparticulate matter adheres to the exposed surfaces of the fabriccomponents. As shown in FIG. 5, box 100, the fabric is first cleanedusing water and optionally a detergent or surfactant to remove any oilsor impurities that may have become deposited on its surfaces duringmanufacture. Before the fabric is heatset so as to stabilize it, theclean fabric is coated, as indicated at box 102, by spraying, dip orlick coating, or other means such as are well known in the art and whichmay be used to provide a carefully controlled application of ahydrophobic and/or oleophobic water based nanoparticle type contaminantresistant liquid solution/suspension to one or both planar sides of thefabric. Preferably, both sides of the textile are so treated.Alternatively, only selected portions of the fabric, such as the lateralside edges, are so treated.

Presently preferred treatment materials comprise a water-basedthree-component system consisting of:

1. an adhesion promoter, which is preferably an organofunctionaladhesion promoter having a functional group which is one of a vinyl-,methacrylate-, epoxy-, amino-, or mercapto-group;

2. a nanoparticulate material comprised of an organic prepolymer whichis preferably comprised of organic nanoparticles such as nanowaxes,including polyethylene or polypropylene, or prepolymers of condensatedsilanes such as methyltriethoxysilane, propyltriethoxysilane,octyltrimethoxysilane, octyltriethoxysilane, or phenyltrimethoxysilaneand the like, with one advantage provided by the use of the silaneprepolymers being the possibility to react with the adhesion promoter tobuild a network of organic prepolymer; and

3. a fluorocarbon polymer, which is preferably a fluoroacrylate orfluoralkyl-polyurethane copolymer, although other similar fluorocarbonpolymers may be suitable.

These three materials are combined in a ratio of from about 10-25% byweight adhesion promoter, 10-25% by weight nanoparticulate material, andfrom about 30-70% by weight fluorocarbon polymer to provide the desiredthree component system. Other coatings may also be utilized.

Following this application of the coating, the fabric is then heatset inthe normal manner suitable for the textile. During the heatsettingprocess, the fabric will be exposed to temperatures in the range of fromat least about 52° C. (125° F.), to about 204° C. (400° F.). Preferablythe fabric will be heated to a temperature of from about 66° C. (150°F.) to about 177° C. (350° F.); more preferably this temperature will befrom about 66° C. (150° F.) to about 149° C. (300° F.) which issufficient to ensure curing and bonding of the surface treatment to thefabric components comprising at least a first surface of the textile.This requires that the fabric be tentered or otherwise stabilized bysuitable means so as to maintain the dimensional stability of thefabric, as shown in box 104. The temperatures required for heat settingcan be simultaneously used for curing the coating, as indicated at box106.

It is presently preferred that the nanoparticle coating have both ahydrophobic and an oleophobic characteristic. However, it is alsopossible to perform multiple coating and curing steps, as outlinedabove, to form a composite coating on the fabric, for example, with afirst coating layer having one of a hydrophobic or oleophobiccharacteristic, and a second or subsequent coating having the other ofthe hydrophobic or oleophobic characteristic, or another desiredcharacteristic. This provides enhanced contamination resistance for thepapermaking fabrics according to the invention. In any event, the fabricmust be provided with a coating layer having one of a hydrophobic oroleophobic characteristic so as to provide effective contaminationresistance properties to a fabric surface.

The fabric is then processed as usual so as to form a seam if necessary,seal its longitudinal edges and so on. If one or both surfaces of thefabric must be sanded or otherwise physically processed so as to renderthem monoplanar, then this is done prior to any application of thenanoparticle coating.

As previously mentioned, fabrics according to this invention may becoated following their installation on the papermaking machine for whichthey were intended, or they may be coated following their manufacture.It may be possible to coat the fabric in either case by means of severalpasses of different nanoparticle anti-contaminant systems so as to gaina composite with increased effectiveness and durability.

After installation on the papermaking machine 12, the fabric 10 can berecoated in accordance with the method of the first embodiment of theinvention, as noted above. This can be done on the papermaking machine12 without the need to remove the fabric 10, thus reducing down time andcosts.

Relative Contamination Resistance (RCR) is an indicator of the abilityof a fabric to resist contamination. RCR is measured by comparing acontrol fabric to a test fabric. In the test, a sample is cut from alarger fabric piece and is washed to remove any dust or grease. Asimilarly sized control sample is also prepared. A suitable length ofdouble sided adhesive carpet tape is then hot pressed at a temperatureof 85° C. (185° F.) and a pressure of 4448 N (1,000 lbs) for 1 min.duration across the narrow dimension of each of the test fabric andcontrol surfaces. The tape is then peeled at an angle of 180° from thesurfaces of each of the test and control samples using a CRE typetensile testing machine at a constant strain rate. The peel forcerequired to remove the tape from the test sample is then compared to thepeel force required to remove the tape from the control sample and isthen expressed as a ratio (RCR). RCR numbers less than 1.0 indicate lesscontamination resistance than the control standard, while RCR numbershigher than 1.0 indicate better contamination resistance.

In laboratory experiments and papermaking machine trials, we have foundthat fabrics prepared in accordance with the teachings of this inventionattained RCR values of from about 3 to about 14 in comparison to theiruntreated counterparts. This difference in RCR values occurredregardless of whether the coating was applied to the fabric on thepapermaking machine in accordance with the first embodiment of theinvention, or if it was applied at the time the fabric was heatsetaccording to the second embodiment. We did find that coatings applied inaccordance with the teachings of the second embodiment exhibited greaterdurability than coatings applied on the papermaking machine according tothe first embodiment.

Fabrics which have been treated in accordance with the teachings of thepresent invention tend to release both water and oily contaminants moreeasily than do comparable, untreated fabrics. We have found that thisimproved propensity of the coated fabric to “give up” water more easilythan a comparable untreated fabric can reduce the amount of energynecessary to dry equivalent amounts of paper by as much as 10% or more.Further, fabrics coated or recoated in accordance with the teachings ofthe present invention tend to run cleaner for longer periods of timewhen compared to similar, uncoated fabrics. A further observed benefitis that fabrics which have been coated with this material have reduceddrag load in operation, with drag loads having been reduced by as muchas 20% when compared to similar uncoated fabrics. Drag load refers tothe load imposed on the drive mechanisms of the paper machine (and thusthe amount of power required to drive the fabric at the desired speed)by the fabric due to the dewatering forces imposed by suction boxes andfoils. Reduced drag loads mean reduced energy consumption which is verybeneficial to mill operating costs. In addition, we have found that TADfabrics whose lateral edges have been so treated appear to better resisthydrolytic degradation at these treated lateral edges when compared tosimilar but untreated fabrics.

While the preferred embodiments of the invention have been described indetail, the invention is not limited to the specific embodimentsdescribed above, which should be considered as merely exemplary. Furthermodifications and extensions of the present invention may be developed,and all such modifications are deemed to be within the scope of thepresent invention as defined by the appended claims.

1. A method of improving contamination resistance properties of apapermaking fabric comprising: a) cleaning a surface of the papermakingfabric, b) applying a nanoparticle surface treatment to at least aportion of one surface of the fabric, c) simultaneously heat treatingthe fabric and curing the nanoparticle surface treatment onto the atleast a portion of the one surface of the fabric, with the nanoparticlesurface treatment being a water based three-component liquidsolution/suspension system, and d) delivering the fabric with the curednanoparticle surface treatment to a customer for installation on apapermaking machine.
 2. The method according to claim 1, wherein thewater based three component system consists of: a) an adhesion promoter,b) a nanoparticle material comprised of an organic prepolymer, and c) afluorocarbon polymer.
 3. The method according to claim 2, wherein theadhesion promoter is an organo-functional adhesion promoter having afunctional group which consists of one of: a) a vinyl group, b) amethacrylate group, c) an epoxy group, d) an amino group, or e) amercapto group.
 4. The method according to claim 2, wherein thenanoparticle material is an organic nanoparticle comprising at least oneof a nanowax or a prepolymer of condensated silanes.
 5. The methodaccording to claim 4, wherein the nanowax consists of one or more of: a)a polyethylene, b) a polypropylene, or c) a prepolymer of a condensatedsilane.
 6. The method according to claim 4, wherein the condensatedsilanes include at least one of: a) methyltriethoxysilane, b)propyltriethoxysilane, c) octyltrimethoxysilane, d)octyltriethoxysilane, or e) phenyltrimethoxysilane.
 7. The methodaccording to claim 2, wherein the fluorocarbon polymer is at least oneof: a) a fluoroacrylate, or b) a fluoroalkyl polyurethane copolymer. 8.The method according to claim 2, wherein weight ratio of the threecomponents in the water based system is: a) from 10% to 25% by weightadhesion promoter; b) from 10% to 25% by weight nanoparticle material,and c) from 30% to 70% by weight fluorocarbon polymer the weightpercents totaling to 100% in the system.
 9. The method of claim 8,wherein the nanoparticle surface treatment comprises 0.5% to 30%nano-solids of nanoparticle material in water.
 10. The method accordingto claim 1, wherein the dimensional stability control comprisestentering the fabric while it is exposed to temperatures in a range offrom at least about 52° C. (125° F.) to about 204° C. (400° F.) to cureand bond the nanoparticle surface treatment onto the at least a portionof the one surface of the fabric.
 11. The method according to claim 1,wherein the nanoparticle coating has at least one of a hydrophobic or anoleophobic characteristic.
 12. The method according to claim 11, whereinthe nanoparticle coating has both a hydrophobic and an oleophobiccharacteristic.
 13. A method according to claim 1, wherein an entiresurface area of the fabric is coated with a nanoparticle surfacetreatment which is the water based three-component liquidsolution/suspension system.
 14. A method according to claim 1, furthercomprising: applying dimensional stability control to the fabric duringthe heat treating.
 15. A nanoparticle coated papermaking fabriccomprising a water based three component nanoparticle coating whichincludes at least (a) an adhesion promoter, (b) a nanoparticle materialcomprised of an organic prepolymer, and (c) a fluorocarbon polymer, andthe nanoparticle coating is cured by heat treatment to bond thenanoparticles to components of the fabric.
 16. The nanoparticle coatedpapermaking fabric according to claim 15, wherein the adhesion promoteris an organo-functional adhesion promoter having a functional groupwhich consists of: a) a vinyl group, b) a methacrylate group, c) anepoxy group, d) an amino group, or e) a mercapto group.
 17. Thenanoparticle coated papermaking fabric according to claim 15, whereinthe fluorocarbon polymer is at least one of: a) a fluoroacrylate, or b)a fluoroalkyl polyurethane copolymer.
 18. The nanoparticle coatedpapermaking fabric according to claim 15, wherein the nanoparticlematerial is an organic nanoparticle comprises at least one of a nanowaxor a prepolymer of condensated silanes.
 19. The nanoparticle coatedpapermaking fabric according to claim 18, wherein the nanowax consistsof one or more of: a) a polyethylene, b) a polypropylene, or c) aprepolymer of a condensated silane.
 20. The nanoparticle coatedpapermaking fabric according to claim 19, wherein the condensatedsilanes include at least one of: a) methyltriethoxysilane, b)propyltriethoxysilane, c) octyltrimethoxysilane, d)octyltriethoxysilane, or e) phenyltrimethoxysilane.
 21. The nanoparticlecoated papermaking fabric according to claim 15, wherein the fabric hasa Relative Contamination Resistance Ratio, which is an indicator of acontamination resistance of a sample in comparison to a controldetermined by measuring a peel force required to remove a tape from asample and a control and then forming a ratio from those values whichranges from about 3 to about 14 in comparison to an uncoated controlsample.